more than one connection in NodeJs

I need to make download script by NodeJs,which limit connections number and speed for each session.

I can read file and write is to response by NodeJs, maybe I can limit speed by sleep package of npm, but how should I support more than one connection to download file in NodeJs?

for e.g when user download it by IDM he/she can see 7 or 8 connection during download.

In apache it can do it by mode_limitipconn and bw_mod

I mean something like RapidShare which limit speed and connections number for each category.

What you want to do is limit access to a resource to only one IP address at a time.

This is fairly easy to do with Node since all requests are served from a single process.

You can enter IP addresses into an object when the request is made and then check that object when new requests come in for duplicates.

If you're using Express and you have your routes in modules, you can put the IP connection object in the top level of the route module.

var connectedIPs = {};

exports.myDownloadRoute = function(request, response) {
  var IP = request.connection.remoteAddress;
  if(connectedIPs.IP) {
    response.redirect("http://mysite.com/download_rules.html");
    return;
  }
  connectedIPs.IP = true;
  // pseudo send a file call, replace this with your code
  send_a_file(function(err) {
    // done sending or error, remove from connectedIPs
    delete connectedIPs.IP;
  }); 
}